In general, an air conditioner is an apparatus configured to condition air using a refrigerating cycle. As illustrated in FIG. 1, the air conditioner is provided with a refrigerating cycle constituted with a compressor (11) compressing a refrigerant to a high temperature high pressure gaseous refrigerant, an outdoor unit (10) including an outdoor heat exchanger (12) for condensing the compressor-passed refrigerant to a high temperature high pressure liquid refrigerant, an expander (21) reducing the outdoor heat exchanger-passed refrigerant to a low pressure low temperature liquid refrigerant, and an indoor unit (20) including an indoor heat exchanger (22) evaporating the expander-passed refrigerant to a low temperature low pressure gaseous refrigerant and absorbing an indoor heat to maintain a room at a low temperature.
The air conditioner is divided into a window type air conditioner and a separated (or split) type air conditioner according to an installation method of an outdoor unit (10) and an indoor unit (20). Although the window type air conditioner and the split type air conditioner are functionally same, but may be different according to installation method.
That is, the window type air conditioner is installed at the window, etc. under the state that an outdoor unit (10) and an indoor unit (20) are integrally assembled to each other in one case, and the separate type air conditioner is respectively installed at the outdoor and the indoor under the state that the outdoor unit and the indoor unit are separated from each other.
As shown in FIG. 2, the typical outdoor unit (10) includes a case (13) formed with an air suction port (13a) sucking air from outside and an air discharge port (13b) discharging the sucked air, a blowing fan (14) formed inside the case (13) for discharging the air sucked from the air suction port (13a) to the air discharge port (13b), and a driving motor (15) rotating the blowing fan (14). That is, in a case the blowing fan (14) is rotated by the driving motor (15), the air sucked from the air suction port (13a) is heat-exchanged via the outdoor heat exchanger (12) and discharged to the air discharge port (13b) via the blowing fan (14).
However, the typical outdoor unit (10) has limitations in that it is formed with a single blowing fan (14) and a diameter of the blowing fan (14) must be enlarged to increase a air volume, or a rotating speed of the driving motor (15) must be increased. As a result, the conventional outdoor unit (10) suffers from disadvantages in that a cavitation is generated at the blowing fan (14), a load is increased to easily destruct the blowing fan (14) and noise and vibration are seriously generated.